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Cranking time to build oil pressure?

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How long is too long to have to crank before the pressure light goes out? With fuelling disabled and a good battery obviously.

I just finished putting my engine back together after a spun bearing. Had a hell of a time getting the oil pump primed and now it still takes 10 seconds of cranking after it sits to get enough pressure to turn the light off. Seems excessive.

Edited by Haze
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My oil light has never come on.


10 seconds is way too long if that's what happens every time you start it.


When I put the new ej257 in, I did not prime the oil system. I started the engine for the first time just like the factory does and just like everyday.



You get oil pressure faster at idle than at cranking rpm.

305,000miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. CHECK your oil, these cars use it.


Engine Build - Click Here

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If I start the car normally, it doesn't take 10 seconds, the light goes out almost immediately after it fires. I briefly get a knocking noise though and I'm worried it's my new rod bearings hitting my new crank because it's firing before there's any oil pressure

If I hold the throttle down (which disables fuelling) and crank for 10 seconds until the light goes out then allow it to start, I don't get the noise.

Everything inside this engine was in great shape except the rod bearings which were all completely beat to hell. It has been noisy at start up since I bought it but I assumed it was just cold piston slap. Now I'm thinking there's something wrong with the oil pump but it makes good pressure once it's running so I'm kinda stumped.

The pickup is a brand new KillerB so there should be no problems there.

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So we have to assume you measured everything before and during assembly and made sure all was in spec.....?

Each main and rod bearing had clearance checked with plastigauge at 3 different points of crank rotation. I know it's not ideal but since I was using a new crank, I felt comfortable with it.

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  • 4 weeks later...

Figured I should update this as the issue resolved itself after I actually drove the car. I'm guessing I left something in the oil pump bypass valve when I took it apart for cleaning, causeing the bypass valve to leak until it opened and allowed the foreign matter to escape

Now, I have to hope that whatever was in there didn't do any serious damage elsewhere.

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